India's Rising Hindu Nationalist

Narendra Modi, a politician who started off as a tea seller, is beloved and despised.

To gauge the political prospects of Narendra Modi, you don't need to know his views on the fiscal deficit, relations with China or the death penalty. But it is important to understand why the man announced Friday as the prime ministerial candidate of India's opposition Bharatiya Janata Party for next year's general election evokes deeper devotion and fiercer opposition than any other politician in India.

Fans and foes alike view the 62-year-old, who has served for 12 years as chief minister of the northwest state of...